Silicon nitride ceramic containing molybdenum disilicide

Abstract

A sintered silicon nitride ceramic having high stiffness consists of, in weight percent, 10.1 to 13.5 aluminum nitride, 6 to 7.5 yttrium oxide, 0.05 to 5 molybdenum disilicide, balance silicon nitride.

I claim: 
     
       1. A sintered silicon nitride ceramic consisting of, in weight percent, 10.1 to 13.5 aluminum nitride, 6 to 7.5 yttrium oxide, 0.05 to 5 molybdenum disilicide, balance silicon nitride. 
     
     
       2. The ceramic of claim 1 consisting of 12.45 AlN, 6.23 Y 2  O 3 , 0.1 MoSi 2 , balance Si 3  N 4 . 
     
     
       3. The ceramic of claim 1 consisting of 12.45 AlN, 6.23 Y 2  O 3 , 2 MoSi 2 , balance Si 3  N 4 . 
     
     
       4. A sintered silicon nitride ceramic having high stiffness made by: ball milling a powder mixture of, in weight percent, 10.1 to 13.5 AlN, 6 to 7.5 Y 2  O 3 , 0.05 to 5 MoSi 2 , balance Si 3  N 4  ; pressing the powder mixture at room temperature; and firing the pressed mixture in a nitrogen atmosphere at 1700° to 1800° C.